As Think Progress points out, Bush is now defining people who are "better off" as anyone earning over $20,000/year. When selling his tax cuts, he defined people who were the "lowest income taxpayers" as anyone earning under $100,000.
Look, this is important. Our media is running around talking about how "rich people" are going to have their benefits cut, as if Bush's cunning plan to save Social Security is to take away Bill Gates's check. Social Security benefits currently max out at $90,000 salary. People who earn $90,000/year are generally not portrayed by the kool kids in the media as "rich" or "wealthy" or even "upper income." Obviously people who earn that much are at the higher end of the income distribution, but especially for such people who live in high cost metro areas, they don't have lives which are noticeably distinguishable from what we think of as "middle class.'